PROJECT SUMMARY/ABSTRACT: Stress urinary incontinence (SUI) and pelvic floor disorder (PFD) are major problems affecting millions of women worldwide. Non-surgical therapies are mostly ineffective and not durable. The most effective are mesh surgeries for SUI and pelvic organ prolapse (POP). However, many women suffered major complications after surgery resulting in the ban of all mesh use for POP in the USA (FDA Apr 16, 2019). We began research in regenerative therapy for SUI in 2002. Our long-term goal is to better understand the pathophysiology and develop a minimally invasive and highly effective regenerative therapy for women with SUI and PFD. In current project, we proposed to activate striated muscle satellite cells in situ with a novel mechanical stimulus we recently developed, Microenergy acoustic pulses (MAP), as a regenerative therapy for SUI and PFD. In severe cases, we propose a combination of myostatin inhibition by clustered regularly interspaced short palindromic repeats interference (CRISPRi) and MAP to achieve better results. Our main hypothesis is that dysfunction of tissue resident progenitor cells is the major contributor to SUI and PFD and myostatin inhibition followed by MAP will provide the best strategy for maximal recovery of urethra and pelvic floor structure and function. The ability to activate and differentiate tissue resident stem/progenitor cells would be a powerful curative approach for many human diseases, and this ability is the basis of the innovations we are developing for focally enhancing muscle regeneration to treat SUI and PFD. These objectives lead us to propose 1). to elucidate and compare the pathophysiology of reversible and irreversible stress urinary incontinence and pelvic floor disorders in vaginal birth injury-induced rat models; 2). to compare the molecular mechanisms of myostatin inhibition and microenergy acoustic pulses on the regeneration of striated muscle satellite cells from reversible and irreversible models of SUI and PFD; 3). to compare the therapeutic and preventive effects of myostatin inhibition and microenergy acoustic pulse therapy in the irreversible rat model of stress urinary incontinence and pelvic floor disorder. Successful completion of the project will form the scientific basis for designing better prevention and treatment for millions of women suffering from SUI and PFD.